Drug interactions
Ritonavir + Voriconazole
Severity: Contraindicated
Ritonavir and Voriconazole: contraindicated interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Full-dose ritonavir substantially lowers voriconazole exposure, risking antifungal failure, while voriconazole may raise ritonavir levels. Low-dose ritonavir used as a booster has less predictable but still potentially significant effects.
What this interaction means in plain words
Ritonavir and Voriconazole are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Ritonavir belongs to Anti Virals; Voriconazole belongs to Anti Fungals.
Why it happens
Ritonavir induces voriconazole metabolism (CYP2C19/2C9) at higher doses, while mutual CYP3A4 inhibition affects ritonavir clearance.
What to do
Avoid high-dose ritonavir (400 mg twice daily or more) with voriconazole. With low-dose ritonavir, use only if benefit outweighs risk and monitor voriconazole levels and efficacy.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Voriconazole
- Avanafil + Voriconazole Contraindicated
- Butabarbital + Voriconazole Contraindicated
- Carbamazepine + Voriconazole Contraindicated
- Conivaptan + Voriconazole Contraindicated
- Dihydroergotamine intranasal + Voriconazole Contraindicated
- Dihydroergotamine + Voriconazole Contraindicated
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Ritonavir with Voriconazole?
MediHelp rates the interaction as contraindicated. Ritonavir and Voriconazole are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Full-dose ritonavir substantially lowers voriconazole exposure, risking antifungal failure, while voriconazole may raise ritonavir levels. Low-dose ritonavir used as a booster has less predictable but still potentially significant effects.
How serious is the interaction between Ritonavir and Voriconazole?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid high-dose ritonavir (400 mg twice daily or more) with voriconazole. With low-dose ritonavir, use only if benefit outweighs risk and monitor voriconazole levels and efficacy.
What other medicines interact with Voriconazole?
MediHelp also lists interactions of Voriconazole with, for example, Avanafil, Butabarbital, Carbamazepine. The full list is on the Voriconazole page.
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